I believe in a handgun that fits well, in the grip and in the trigger reach. It is also important that it "point" well for the user. Yes, it is possible to train around fit and point issues, but I don't believe in fighting nature when you can work with it.
My personal experience with Glocks started in 2002, when, for reasons too long to get into here, I had to stop using 1911 pistols as duty weapons. I could not go back to my beloved sixguns, because I had not "grandfathered" any of them when we switched to certain .40 DA autos in 1997. By 2002, Glocks were in their 3rd generation, and these new Glocks pointed well for me. I could never seem to shoot quite as nice and tight groups with a Glock as with a 1911 or sixgun, but the real-world difference seemed negligible, and I figured I would get better.
Well, I was frustrated in my efforts to get better, shooting several thousand rounds over a couple of years. In 2004, I handled a SIG P229, with the new DAK trigger system, and a factory short trigger. This was a revelation for me; while I had long known I liked the feel of the P228/P229 grip, the standard trigger was to much of a reach for good DA shooting. Once I verified that I could qual with a DAK version of the P229, I pulled out the credit card. I fired the P229 cold, for the first time, on my agency's qual course, and fired a higher score than I had ever achieved with the Glock G22.
As soon as I bought one of the mandatory Safariland 070 duty holsters, and ran 500 rounds through the P229, I was carrying it on the street. The DAK trigger meant that I did not have to re-learn the DA-to-SA transition. I had just spent well over a thousand dollars in the transition, but IMHO, it was worth it. Subsequent shooting with a "traditional" DA P229 showed that it was not the DAK trigger system that made the P229 so good for me, but the short factory trigger. I wish I had known that a couple of years sooner, because I did not get my money back that I had spent on a couple of duty-sized Glocks, and the baby Glock I got for back-up.
I believe that the Glock's chunkier grip worked against me, as my pinky fingers are quite short, and were contributing little to maintaining a grip, so shot-to-shot recovery was less consistent. Also, the wide-bodied Glock trigger always bothered me; I like a narrower trigger. The mushiness of the Glock trigger pull certainly did not help.
Just to be clear, I am not knocking Glocks; they just do not fit me well, and that wide trigger appeals to some.
My $0.02 on the XD: I am concerned about not being about to work the slide unless the grip safety is fully depressed. I can see that being a problem if one or both hands are incapacitated due to injury during a gunfight. The XD is a toy for pistol matches.